Large Language Models

In March 2023 a New York law firm filed a brief in Mata v. Avianca, a personal-injury suit against the airline, citing court decisions that supported its client, among them Varghese v. China Southern Airlines. Six of the cited decisions did not exist. One of the lawyers had found them with ChatGPT, and when he asked it whether they were real, it replied that they were and that they "can be found in reputable legal databases such as LexisNexis and Westlaw." On 22 June 2023 Judge P. Kevin Castel of the Southern District of New York sanctioned the two lawyers and their firm $5,000.